The long-term objectives of this laboratory are: (1) to understand the mechanisms underlying the metabolic (functional) reorganization of the developing and established central nervous system (CNS) to peripheral or central nervous system damage, (2) to determine the behavioral consequences of such reorganizations, (3) to determine anatomical and physiological factors, which can enhance or retard CNS reorganization and subsequent recovery of function, and (4) to apply the knowledge gained from animal plasticity studies to the study of the functional plasticity-recovery of function relationship in human subjects possessing somesthetic deficits produced by lesions of the peripheral nervous system (e.g. peripheral nerve trauma, limb amputation, phantom-limb responses) or CNS (e.g. stroke, neoplasia). Such human studies would involve the use of the (11C) or (18F)-2DG, positron emission tomography technique, with which the principal investigator has had experience. The specific aims of this proposal are: (1) to determine the effects of CNS maturation on the extent of metabolic (functional) reorganization at both subcortical and cortical levels of the CNS, (2) to determine anatomical changes in first somatosensory (SI) cortex associated with the deafferentation-produced reorganization, (3) to determine the behavioral consequences of the observed metabolic reorganization, and (4) to determine the effects of intervention on the extent of metabolic (functional) reorganization. The precise organized rat facial vibrissa SI cortical "barrel" system will be utilized for such metabolic plasticity studies. The reorganization of the functional (metabolic) representation of a single, centrally-positioned facial vibrissa (C3), which is spared following denervation of the remaining vibrissae, will be examined at subcortical and cortical levels of neonatal and adult rats under different experimental conditions using the quantitative (14C)-2 deoxyglucose metabolic mapping technique. Behavioral consequences of the metabolic reorganization of the spared C3 vibrissa will be examined using a species-typical locomotor response tests.